Arc welding is quite often used as a method to build up, clad, or hardface metal objects, thereby placing a weld metal of a desired alloy onto the surface of another metal. Commonly, the composition of the clad or hardfacing material is significantly more expensive than the metal it is being placed on and therefore it is desirable to minimize the thickness of the weld metal. But in the process of welding, the cladding or hardfacing weld metal may be diluted by the base metal and more weld metal may be added to obtain the desired properties.
In other cases, the cladding or hardfacing weld metal, when applied directly to a base metal, may form an undesirable layer that may not survive in service. In such cases, an intermediate layer of weld metal may be added to avoid the formation of this undesirable layer. For example, when a copper/nickel cladding is added to a mild steel base plate, the mixture of the copper (from the cladding) and the iron (from the steel) may combine to form a layer that tends to be crack sensitive. In order to eliminate the intermediate layer, a low heat process such as GMAW-short arc transfer may be used. The copper/iron mixture layer (sometimes called admixture) is kept low enough to prevent cracking but this process is limited to the short arc transfer range and is, therefore, slow. When the procedure is increased to improve productivity, and a traditional GMAW-pulsed spray or GMAW-Spray transfer is used, the heat increases and the mixture of copper and iron increases to an undesirable level. Thus, there is a need for a high productivity, low heat input welding process to build up, hardface or clad with a minimum admixture.
Further limitations and disadvantages of conventional, traditional, and proposed approaches will become apparent to one of skill in the art, through comparison of such systems and methods with the present invention as set forth in the remainder of the present application with reference to the drawings.